In a radio communications system, to improve working efficiency of a power amplifier and protect the power amplifier from being damaged by a received noise signal that has an extremely large peak value, a transmitter needs to perform clipping processing on a to-be-transmitted signal before transmitting the signal. Currently, a widely used clipping manner is a crest factor reduction (CFR) technology, which is a signal processing method for smoothly suppressing a signal peak. Clipping may cause an increase of error vector magnitude (EVM) of a signal, and make the signal distorted. Therefore, in a case in which a signal is ensured to meet an EVM indicator in clipping processing, a peak-to-average power ratio (PAPR) of the signal is reduced as much as possible to ensure that the power amplifier operates within a linear range.
In the prior art, a transmitter performs clipping processing by using one level of clipping, for example, abase station implements clipping in a remote radio unit (RRU), which limits a clipping scalability function.